Route reliability record
SAN→DTW
San Diego to Detroit
- Flights
- 1,269
- Period
- September 2025 to August 2026
- Distance
- 1,956 mi
- Carriers
- 2
This route earns an A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.3%. When something does go wrong the average delay runs roughly 55 minutes. That rests on 1,269 SAN to DTW flights, with a median arrival 7 minutes early.
Best time to fly SAN to DTW: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 89.3% of the time and Tuesday flights 94.0%, against 85.9% for the route overall.
Set against the rest of the country, this route's record is 9 points better than the US average of 77.3%. That gap is worth roughly 86 fewer late arrivals for every thousand flights.
Key figures
On time
85.9%
Arrivals under 15 minutes late, of 1,257 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
0.87%
National rate is 1.89%
Best carrier
Delta
86.1% on time across 1,250 flights
These figures cover 1,269 flights between September 2025 and August 2026. The median arrival is 7 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
Which airline is most reliable on SAN to DTW
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,250 | 86.1% | 52 min | 0.80% | A+ |
| Spirit Airlinesthin sample | 19 | 72.2% | 67 min | 5.26% | C− |
Flight by flight
Flights on SAN to DTW
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Departure window
The best time of day to leave
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 1,269 flights.
- 5am–8am365 flights89.3%
- 8am–11am—
- 11am–2pm383 flights81.4%
- 2pm–5pm191 flights83.7%
- 5pm–8pm—
- 8pm–5am330 flights88.7%
Scale runs 75% to 95%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 81.4% on time against 89.3% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 11am–2pm window is the busiest, with 383 flights scheduled in it.
Explore
Filter SAN to DTW by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On SAN to DTW, the best departure window is 5am–8am at 89.3% on time and the worst is 11am–2pm at 81.4%, a real gap of 7.9 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am89.3%
- 8–11am—
- 11am–2pm81.4%
- 2–5pm83.7%
- 5–8pm—
- 8pm–5am88.7%
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 21 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 72.5% on time, 21 points below October, the best at 93.2%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. September was the busiest month here, with 119 flights.
Across the week, Tuesday is the strongest day at 94.0% on time and Thursday the weakest at 81.1%, a spread of 13 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 9,314 reported delay minutes.
- 37%Late-arriving aircraft
- 34%Carrier
- 28%National Airspace System
- 0%Extreme weather
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 9,314 reported delay minutes here, that single category outweighs weather by 37 to one. The split is drawn from 9,314 reported delay minutes.
The largest share of delay minutes, 34%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 3,180 of the 9,314 delay minutes reported here.
Cancellations are rare at 0.87%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 2.8% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 1,956 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 73.5% on time across 1,269 flights, 12 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 12 points of difference.
The sample behind these figures is 1,269 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in DTW after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. October runs 93.2% on time and July 72.5%, a swing of 21 points. If the dates move at all, move them out of July before you think about anything else. 1,257 completed flights over 12 months sit behind that.
Common questions
SAN to DTW questions
How often is SAN to DTW delayed?
About one flight in seven arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 14.1% of the 1,269 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 55 minutes on average.
How reliable is SAN to DTW compared with the rest of the country?
85.9% of flights arrive on time here against a national 77.3%, a difference of 9 points in its favour. That is worth a A+ on this site's grading scale.
What time of day has the fewest delays on SAN to DTW?
The 5am–8am departure window is the strongest at 89.3% on time. The 11am–2pm window is the weakest at 81.4%, 8 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on SAN to DTW?
July is the weakest month at 72.5% on time, compared with 93.2% in October. Across the year that is 21 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- DTW to SAN — the return legseparate record
- San Diego International (SAN) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- SAN to SFO, a related route59.5%
- ORD to DTW, a related route71.1%
- SAN to DEN, a related route78.4%
- Delta Air Lines on-time record86.1%
- Spirit Airlines on-time record72.2%
- Why the first flight of the morning is statistically safest
- Worst months to fly in the US, ranked by the data
Direction matters. SAN to DTW and DTW to SAN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.